When Scots went to the polls to vote for independence from the United Kingdom in September 2014, the role of the Queen came under scrutiny.
At the time, the leader of the Scottish National Party (SNP), Alex Salmond, pledged that if voters backed exiting from the 300-plus year Union, Elizabeth II would remain "Queen of Scots."
Polling at the time suggested Salmond accurately gauged the popular mood on the Queen -- 52% wanted to keep her. The question was moot, however, as Salmond famously miscalculated Scotland's mood on independence, which was voted down 55% to 45%.
Of the many lessons of IndyRef 2014 in Scotland, one solid takeaway was that the Queen was not directly part of the problem.
In Northern Ireland, however, during much of her reign the opposite was true.
The 30 bloody years of violence known as "The Troubles" pitted UK unionists against Irish nationalists, with the British Crown emblematic of much that divided the province.
Unionists are loyal to the Crown and the traditional British values they believe it enshrines. For Irish nationalists, it is the symbol of the British forces who subjugated their ancestors and annexed their land.
Charles' favorite great-uncle, Lord Louis Mountbatten, the last British Viceroy to India, was murdered by the Irish Republicans along with several of his grandchildren. The message to the monarch was unmistakable: Her bloodline were legitimate targets.
Queen Elizabeth II shakes hands with Deputy First Minister of Northern Ireland Martin McGuinness as First Minister Peter Robinson looks on at the Lyric Theatre on June 27, 2012 in Belfast, Northern Ireland.
Her public reply came many years later, on a 2012 visit to Northern Ireland that followed the relative peace brought by the Good Friday Agreement, when she shook the hand of one of the republicans most associated with the groups behind the violence of the past, Martin McGuinness.
That government officials recommended she take McGuinness's hand speaks to her power on all things Union. She is not the Union, but a symbol of it. McGuinness's Irish nationalist republicans had reluctantly ended their "armed struggle" and remain, for now, inside the Union.
So, to think Queen Elizabeth has little relevance to today's Union would be to misread her reign.
She was a unifying force, wielding her soft power delicately and discreetly with the singular aim of keeping together the Union and the vestiges of the Empire, the Commonwealth.
Soft but real unifying power
The Queen's ability to understand and navigate the complexities of Edinburgh's relationship with London in a way that English politicians -- particularly Conservatives -- rarely grasp, and to overcome her own personal suffering at the hands of Irish nationalists, spoke volumes of her dedication to unity.
It is no coincidence that her late husband, Prince Philip, was titled the Duke of Edinburgh, or that her son, Charles, was invested as Prince of Wales within the walls of Caernarfon Castle in Wales, or that her grandson, Prince William, the Duke of Cambridge, is also titled the Earl of Strathearn in Scotland. As heir to the throne, William now inherits the title of Duke of Rothesay in Scotland formerly held by his father.
Nor is it coincidence that the Queen spent many months of the year at Balmoral Castle in Scotland -- which wasn't just one of her favorite residences but a place and culture in which she felt at home -- enjoying the wild rugged moorlands that few English politicians ever sample. Indeed, it was at Balmoral that she had her final public engagements -- accepting the resignation of UK Prime Minister Boris Johnson and inviting his successor, Liz Truss, to form a new government. Two days later, the Queen's close family gathered there as the news of her death was shared with Britons and the world.
Queen Elizabeth II, left, welcomes Liz Truss during an audience at Balmoral, Scotland, where she invited the newly elected leader of the Conservative party to form a government on September 6.
Elizabeth styled herself as a figure sympathetic to the whole United Kingdom. Her unifying power in this regard was soft, but real.
The Queen never professed to feeling more English than Scottish, or to being any less a figure for the Northern Irish than the Welsh.
Old animosities to the Crown, be it Irish, Scottish or Welsh, predated her reign by more than a generation. For many people in all parts of the UK, the Queen embodied consistency, custom and continuity; her son is likely to do the same.